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Daryl Bem and the Replication Crisis
- theparanoid 9y agoScott Alexander wrote about Bem and parapsychology back in 2014, http://slatestarcodex.com/2014/04/28/the-control-group-is-out-of-control/ http://slatestarcodex.com/2014/04/28/the-control-group-is-ou...
- xmonkee 9y agoOh man, I've been looking for this article for ages. When the new Bem article came out yesterday I hunted for it again and couldn't find it. Thank you so much!
- nkurz 9y agoI thought the back and forth between Johann and others deep in that thread added a lot to the piece: http://slatestarcodex.com/2014/04/28/the-control-group-is-out-of-control/#comment-67143 http://slatestarcodex.com/2014/04/28/the-control-group-is-ou... One conclusion seems to be that seeing successive replications of an experiment that you believe to be flawed does not mean that one should eventually lose one's doubt. Unfortunately, it also does not mean that one's doubt is justified, and that the results can safely be ignored. Rather, it means that at some point (if you want to improve your knowledge) you have to figure out some way to analyze the experiment from another angle and remove (or confirm) the base cause of the doubt.
- Bartweiss 9y agoA line from Andrew Gelman I really appreciate: "Again, they’re placing the original study in a privileged position. There’s nothing special about the original study, relative to the replication. The original study came first, that’s all. What we should really care about is what is happening in the general population." There are two very different questions about replication. One is whether the study got its results by chance, including forced-chance techniques like forking paths and salami slicing. This can be handled with either preregistration or exact replication. (And at p < .05, replication is a must because 5% of un-forced results will still be off!) But the other is whether the study got its non-chance results by methodological flaws or an actual insight about the world. Exact replications are no good for this - doing the wrong thing twice is no better than doing it once. The power poses study, for instance, used testosterone sampling procedures that introduced known confounders. What would help is a study equivalent of N-version programming: settle, preferably preregistered, on multiple tests for the same effect. If they all work, you win. If some work (repeatably) and others don't, you've either made a design error or found a different effect than the one you were looking for. This also explains how to work your confidence levels (a topic discussed in that SSC thread). You can't replicate a study endlessly and gain confidence every time. Given a prior for P(effect), exact replications boost P(effect ∪ bad study), and your P(effect) belief is bounded by the odds of a methodology error. It's a point I'd never considered until that SSC post, and one a lot of actual researchers still seem to miss.
- scribu 9y agoThis is clearer and a lot more comprehensive than the Slate piece. Thanks for pointing to it!
- rspeer 9y agoI love the details in that article. "For example, Savva et al was listed as an “exact replication” of Bem, but it was performed in 2004 – seven years before Bem’s original study took place. I know Bem believes in precognition, but that’s going too far."
- dkbrk 9y agoThat's a great article. Scott Alexander is always worth a read. I especially love this bit: > Two experimenters in the same laboratory, using the same apparatus, having no contact with the subjects except to introduce themselves and flip a few switches – and whether one or the other was there that day completely altered the result. For a good time, watch the gymnastics they have to do to in the paper to make this sound sufficiently sensical to even get published. This is the only journal article I’ve ever read where, in the part of the Discussion section where you’re supposed to propose possible reasons for your findings, both authors suggest maybe their co-author hacked into the computer and altered the results.
- lloydde 9y agoFrontpage six days ago with different title https://news.ycombinator.com/item?id=14364573 https://news.ycombinator.com/item?id=14364573
- nkurz 9y agoIt's been briefly on the front page a couple more times as well (click "past" on the top of the page), but each time quickly flagged off by users. Likely this was because many of the early comments were concentrating on the flaws in article rather than the intriguing underlying concept. Let's see if we can keep this one alive by staying focused on the interesting parts.
- dang 9y agoYes, we invited this repost in the hope that a different title would make for a less lame discussion: https://news.ycombinator.com/item?id=14372695 https://news.ycombinator.com/item?id=14372695.
- hueving 9y agoHow do you invite someone to repost something?
- Tomte 9y agoThey get an email with a special link. If you resubmit using that link the submission gets insta-promoted to the lower end of the front page.
- dang 9y agoRight, which usually guarantees a few minutes of frontpage time and community interest (or disinterest) takes it from there. This is described at https://news.ycombinator.com/item?id=11662380 https://news.ycombinator.com/item?id=11662380 and links back from there.
- misnome 9y agoResampling the comments until you get the results you want is ironic, considering the problems this causes in some (related to the article) scientific fields.
- nkurz 9y agoIf you can get past the linkbait title and some questionable word choices on the part of the author, this is actually an excellent article. The article is not trying to convince you that ESP is real, at least not in the sense of in-the-world reality. Rather, it's an article about the standards of scientific proof, showing that there are cases where standard statistical practices can "prove" apparently absurd results. The issue is that in general, it's hard to tell the difference between "absurd" and "unexpected". In theory, the scientific method is about designing experiments that produce replicable results that cannot be explained by current theory, and then refining (or replacing) the theory until the can explain the new results, while still making correct predictions about all cases covered by the old theory. But what do you do when results are obtained that violate the foundations of science, such as the time order of cause and effect? Naturally, one should start by being skeptical of the experiment. Was the data accidentally recorded wrong? Was the data inappropriately filtered before being analyzed? Is the experimenter lying about the data that was obtained? Usually, thinking about these issues yields some apparent cause of error that would explain the unexpected results without violating one's basic beliefs. Unfortunately, an apparent reason for disbelief can often be found even if the results truly are impeccable. Often, the result is that doubters continue their disbelief, and the believers continue believing, until one faction or the other retires from the field and the other belief becomes "consensus". What Bem has done is to design an experiment that surpasses the statistical standards of many fields, yet "proves" a result that on the surface seems impossible. Most of the usual scientific errors have been avoided, and his methodology and analysis are better than most. One possibility is that our current conceptions of causality are wrong: we think that for A to cause B, A must happen before B, but in fact this is not a requirement. Another possibility is that something is grossly wrong with our current interpretation of scientific results, and many longstanding theories which are considered "scientifically" proven may in fact be mistakes, or at least have no more "proof" than Bem has managed to show for ESP. For most scientists, both of these answers are problematic, yet it would seem that at least one of them must be true. One twist is that some believe that Bem's goal is not actually to prove that ESP is correct, rather to show that the foundations of science are faulty: http://andrewgelman.com/2013/08/25/a-new-bem-theory/ http://andrewgelman.com/2013/08/25/a-new-bem-theory/.
- ianai 9y ago
- onli 9y agoI might have missed it in this rather long article, but I think the whole debate could use some people more that have read Karl Popper and are familiar with Positivism vs Falsifiability. I would not be surprised if all this amounts to is that you can of course "replicate" results if you try often enough, and ignore the falsifying results when it did not work. I mean, of course the big problem is that applying strict falsifiability to social sciences does not work. You can always find a counter-example, the problems studied do not work like that. It is hard to reconcile this, but I think that is the heart of the replication crisis (together with some bad statistics). But (having done a PhD in a somewhat related field) I see only two options: 1. We need a complete overhaul of how experiments and study results are published, so that observers can see the failed results and we can try to assess how often a theory hold up 2. We have to limit non-hard sciences to questions that are not ambiguous, where one well-done negative result really shows a theory is wrong. Of course, there is a third option: Just continue as it is now and ignore all results that seem unlikely, because given how those fields work, they are most likely wrong.
- adrianN 9y agoWhy does strict falsifiability not work in social sciences? You just need to state your theories better if you can otherwise find counterexamples easily. Physicists don't say "smash these two particles together and you'll see a Higgs Boson", they have sufficiently nuanced theories that sifting through petabytes of data to find what you claim exists is justified.
- onli 9y agoIt's about the problems you can study. Take the Cornell Food Lab as example. One of the examples was that people will eat less sweets if they are stashed away and not fully visible on a table. It's interesting and it might very well be true, overall. But it is absurdly hard to know for sure. For one, devising an experiment for this is very hard. But the main problem is that you will absolutely find at least one person that eats more sweets when they are stashed away. So, the theory is wrong? Not really. It might be an invalid theory though. But if you think that, there are very few things those fields could study. I'd say there were no use for them. > they have sufficiently nuanced theories that sifting through petabytes of data to find what you claim exists is justified. That does not sound like searching for falsifiability to me. However, it sounds like the workaround I also tried: Backing a theory - that expects an overall result, not to be true for each individual - up with as much data as possible so one can reasonable assume it is true. But that's not really the correct approach. No, for something like the Higg Boson they try to see it or its effects (and if they were not to see it in the right circumstances, the theory were false). Might be a bad example though given how it touches physicists theory building.
- Bartweiss 9y agoThis is a very worthwhile article in terms of simple facts. It covers largely the same ground as the Slate Star Codex piece a few years back, updated and made more accessible. But I can't help wondering at the article's urge to challenge all of science or none of it. It feels rather protective, as though the author is unwilling to countenance the possibility that studies in psychology (and related subfields) in particular are in jeopardy. "The replication crisis as it’s understood today may yet prove to be a passing worry or else a mild problem calling for a soft corrective. It might also grow and spread in years to come, flaring from the social sciences into other disciplines, burning trails of cinder through medicine, neuroscience, and chemistry." This brackets the possible outcomes, certainly. But it's one hell of an excluded middle, implying that perhaps there will be no serious errors found (already out of the question) and perhaps entire fields will be wiped away. Realistically, we have a much better understanding of the crisis than this already. Medicine has a disturbing number of process issues, but many (like ignoring NNTH) are unrelated to replication errors. The neuroscience result is serious but specific to fMRI studies, and the chemistry link there is aggressively misleading. It concerns documentation and yield statistics for very real reactions, not the sort of "whole theories are junk" issues social psych is up against. There is effectively zero chance that chemistry and psychology come out of this looking equally good (or bad), and I'm disturbed by the equivocation. "If you bought into those results, you’d be admitting that much of what you understood about the universe was wrong. If you rejected them, you’d be admitting something almost as momentous: that the standard methods of psychology cannot be trusted, and that much of what gets published in the field—and thus, much of what we think we understand about the mind—could be total bunk." This is hyperbole, fine, but it still aggravates me in light of the other section. These two things are not comparable! One contravenes fundamental physics, the other says most psychology results are unproven (not even false, just unproven). Michael Inzlict says of the crisis "I feel like the ground is moving from underneath me, and I no longer know what is real and what is not," but even he doesn't consider this comparable to the collapse of basic physics. A quick look at the Engber's other articles suggests a similar thread runs through all of them. He covers specific replication failures, but runs headlines like "Science Is Broken. How Much Should We Fix It? More rigor in research could stamp out false positive results. It might also do more harm than good." He writes about Gary Taubes (recently) as though past errors on carbs make Taubes (consistently failed) claims true. The list goes on. There is a weird, pervasive implication - not just in Engber's writing - that the replication crisis means we must throw everything up in the air equally. That maybe ego depletion is still true-as-studied, and maybe basic chemistry and biology are false. This clouds needless confusion around the information we have already, and fuels a "teach the controversy" attitude on topics from stereotype threat to insulin. We would be better served by a less hedged but more cautious approach that makes real effort to discuss how confident we should be on what points.
- valuearb 9y agoit really brings into question whether psychology can ever be a science.
- jonstokes 9y agoFrom the article: "A few students—all of them white guys, Wu remembers—would hang around to ask about the research and to probe for flaws in its design. Wu still didn’t believe in ESP, but she found herself defending the experiments to these mansplaining guinea pigs. " Was this race- and gender-related jab really necessary? (Honest, non-rhetorical question.)
- jerryr 9y agoYeah, that seemed really incongruous. It left me wondering if I was missing some industry-specific context.
- nkurz 9y agoNo, it was a mistake and distracts from the article. But empirically, the 3 previous discussions about this article have been too distracted by this "easy target" to discuss the interesting (to me) underlying issues, and have been user flagged to death. You can find others' answers to your question by searching for the earlier postings. So without malice, I downvoted your comment not because it's wrong to ask, but to try to move it to the bottom of the page where it can do less harm.
- jonstokes 9y agoThanks for the heads-up and backstory. I didn't know this article had this kind of history here on HN.
- Dowwie 9y agoLast week, I attended PyCon in Portland. Two keynote speakers were from academia. Both speakers touched on challenges that scientific communities are having with regards to replication. One attempt to address this challenge is by using, and sharing as reference material, Jupyter notebooks (Python) used during research.
- Bartweiss 9y ago> and sharing as reference material I'm hugely in favor of this. Lots of replication-crisis stuff focuses on handling statistical issues like salami slicing. That's great, but it's a one-problem fix. Releasing more comprehensive information is a far, far bigger advance, which enables everything from catching data fraud to verifying statistical analysis. Reinhart and Rogoff, for instance, was afflicted with nontrivial formula errors in the analysis. A standard of releasing data and code with papers would have allowed this to be discovered in months rather than years.